Before Goenkaji passed away, he was having knees problem for some time, and hence, he wasn't teaching as many of the vipassana meditation courses as what he used to be teaching until the presence of the knees problem, just like many other people with certain degrees of conscience or universal common sense would take some physical rest, refraining from performing certain physical activities, to be looking after the well-being of the physical body. Also, meditation practice to be keeping the mind focusing in the present moment being aware of the selfless impermanent changes without craving or aversion, is not only be limited to particular sitting posture.
However, there were some minds that were under the influence of ignorance and egoism, that had misunderstanding about self-realization towards the truth of selflessness and impermanence, and about transcending or going beyond selfless impermanent changes void of the desire of craving and aversion, they were being disappointed by the fact that Goenkaji, as a meditation and dhamma teacher, would still be suffering from certain physical decaying and aging process of weakness, limitation, injury, disability or illness, and were criticizing Goenkaji for not performing sitting meditation for many hours a day like all the participants of the vipassana meditation courses due to the knees problem, as they expect him and all the others who are the meditation and dhamma teachers, who have attained self-realization towards the truth of selflessness and impermanence, and have transcended or gone beyond selfless impermanent changes being free from craving and aversion, that they shouldn't be limited by any selfless impermanent changes of decaying, aging, pain, discomfort, injury, illness, weakness, limitation or disability.
They think, understand and expect that 'non-craving' and 'non-aversion' means, if one is under the hot sun for a prolonged period of time, one shouldn't move away from the sun even if the skin is getting seriously burnt, as one is practicing 'non-aversion'. Or, if one's hand comes in contact with hot burning object, one shouldn't move the hand away from the hot burning object, as that is 'craving' towards not getting painful injury.
That is the indication of deep ignorance. The practice of non-craving and non-aversion is nothing to do with such ignorant thinking and understanding.
Just like Siddhartha Gautama Buddha, all these dhamma teachers were delivering the dhamma as it is, showing all and everyone about the selfless impermanent physical body is still the same selfless and impermanent upon the attainment of self-realization towards the truth of selflessness and impermanence, where there will be continuous selfless impermanent changes of decaying, aging, weakness, illness, injury, discomfort, or pain ceaselessly happening, and eventually, ceased functioning and decomposing. However, most minds that are under the veil of ignorance and egoism, would prefer and imagine that upon self-realization or enlightenment, the mind can control everything to be the way that it desires, where the physical body will become immortal, forever youthful and powerful without any selfless impermanent changes of decay, aging, weakness, discomfort, illness, injury, or limitation. Similarly, many minds would think, desire and expect that the realization of timelessness will make the life existence of the physical body and thinking mind to become immortal and will be continuously existing infinitely from now and onward, in the exact good condition of the present moment, without any further selfless impermanent changes of decay, aging or death.
The realization towards the truth of all and everything is selfless and impermanent doesn't change the truth being what it is.
Selfless impermanent changes is still what it is even after self-realization towards the truth of selflessness and impermanence. It doesn't mean that selfless impermanent changes ceased happening upon self-realization. The realization towards the truth of names and forms doesn't change the names and forms being what they are, being selfless and impermanent, however, the selfless mind will be free from suffering that derived from being ignorant towards the truth.
Transcending or going beyond selfless impermanent changes without the desire of craving and aversion, is about the selfless mind is able to remain equanimous, under any conditions and situations, not being determined or disturbed by the selfless impermanent changes that are happening ceaselessly in the selfless impermanent physical body and the selfless impermanent modification of the mind, as well as not being determined or disturbed by the mind perception of all kinds of pleasant and unpleasant or agreeable and disagreeable names and forms or experiences. It doesn't mean that one shouldn't perform any necessary action to be looking after the well-being of the body and mind, or one should be torturing or abusing the body and mind deliberately, or there won't be any physical and mental decaying, weakness, illness, injury, limitation and disability that can be limiting or restricting the body and mind in certain way, where one should be continuously performing all kinds of physical and mental activities as free as one desires, if one is practicing non-craving or non-aversion.
It's about the selfless mind is able to accept or respect the reality in the present moment now, as it is, that is not necessarily pleasant or agreeable, not being determined or disturbed by the selfless impermanent decaying or aging process, remain equanimous, and void of the disturbed suffering state of mind, even though there are some physical and mental discomfort, pain, weakness, illness, injury, disability or limitation arising and passing away, due to the decaying and aging process of the selfless impermanent physical body and the selfless impermanent modification of the mind.
It is not about forcing or challenging the body and mind to go beyond any limitation that is there in the present moment, but it is about living life as it is, performing actions that is within the selfless impermanent condition and ability of the body and mind that is available and possible in the present moment now.
When there is physical tiredness, weakness, illness or injury, the physical body needs to take rest from certain physical activities.
Similarly, when there is mental tiredness, weakness, illness or injury, the mind needs to take rest from certain mental activities.
And all are impermanent.
It's a very simple understanding.
Inquire the truth of everything.